work.suroh.tk/node_modules/rxjs/operator/single.d.ts

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2019-12-02 12:22:45 +00:00
import { Observable } from '../Observable';
/**
* Returns an Observable that emits the single item emitted by the source Observable that matches a specified
* predicate, if that Observable emits one such item. If the source Observable emits more than one such item or no
* such items, notify of an IllegalArgumentException or NoSuchElementException respectively.
*
* <img src="./img/single.png" width="100%">
*
* @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
* callback if the Observable completes before any `next` notification was sent.
* @param {Function} predicate - A predicate function to evaluate items emitted by the source Observable.
* @return {Observable<T>} An Observable that emits the single item emitted by the source Observable that matches
* the predicate.
.
* @method single
* @owner Observable
*/
export declare function single<T>(this: Observable<T>, predicate?: (value: T, index: number, source: Observable<T>) => boolean): Observable<T>;